In recent years, the application of cloud computing (cloud) to a data center (DC) has been advanced. In a general cloud, a DC provider virtualizes and constructs a plurality of corporate IT systems or a plurality of business systems within a corporate enterprise on an information processing system having servers, storages, and networks. Because the cloud is based on a virtualization technology, the cloud is excellent in scalability as compared with a physical system. On the other hand, because the plurality of corporate IT systems are integrated into single information processing system, the plurality of IT systems are mixed together and complicated. For example, the virtualized IT system for each client, or the virtualized business system, which are integrated into the cloud is called “tenant”.
For the purpose of avoiding the complicated configuration, in an example of the cloud currently provided, server resources and storage resources can be customized in the IT system configuration to be provided to the clients, but the coupling configuration of the network is fixed. For that reason, the application of the corporate IT systems to the cloud is limited.